I recently bought a brand new Apexi N1 Evo Exhaust, which I found upon delivery is JASMA certified. Once I saw this badge, I figured it was going to be pretty quiet. After installing it on my stock FD, I was shocked to find how quiet the exhaust is. Does anyone have this version of the exhaust with the pre-cat removed? I know it'll get a bit louder when putting a downpipe on, but I was really hoping for something slightly louder than this. The only videos I found with the Apexi N1 exhaust installed were over a decade old and sounded nothing like what this does.

 

You probably won't notice much of a difference with just the downpipe either. The main cat keeps it pretty quiet overall and you don't want to open that up until you have the rest of the supporting mods (fuel, Computer etc.) I believe the Evo series also contains another resonator is that correct? Does your new catback have another muffler or cherrybomb looking thing in addition to the muffler? The older N1s were just straight through piping with a can which is why they were pretty loud.

 

Yeah, it has a resonator shortly after the catback flange and then the N1 style rear muffler. However, this N1 muffler is a bit different internally than other N1 systems I’ve had from them on other vehicles. It is SUPER high quality, but rather disappointing in the sound department.

 

As EPA and other government entities have come down hard on companies, they've tended to go quieter by necessity. It will probably sound really good if or when you get around to a high flow cat or no cat if you like loud. It also may not be loud in the car but sound really good behind the car which would be considered a well engineered exhaust. The HKS Hi Power I have on the wife's S14 is like that, straight through from the turbo back, not loud in the car and no drone but if you are in the direction of the muffler, its pretty serious. Have you had anybody follow you or had somebody else drive your car while you follow them to see what it really sounds like? It will sound totally different stopped and revving than while you are under a load

 

70 mm pipe is quite small for a JDM aftermarket exhaust. Most of them have at 76 or 80 mm from the downpipe.
I wonder if that's part of how they kept it so quiet.

How old was your previous exhaust? The fact that it's brand new may also be part of why it seems to quiet, despite having a straight-through muffler.

 

I went from a stock exhaust, this is on a 100% stock car. I'll keep it on the car and once I have a chance to do a pre-cat delete downpipe and a high flow main cat, I'll determine whether or not it sounds how I'd like it to sound.